In the oil and gas industry, as with other industries, it is desirable to reduce the time taken to carry out specific operations. This can be achieved in some instances by improvements in technology, which reduce the time taken to carry out these operations. One particular instance is to actuate down-hole tools remotely by applying pressure to the well bore or well tubing string, as used with hydraulic set packers, which are known in the industry. The limitation of this method is that it may be advantageous to carry out pressure testing, prior to actuating the down-hole tool, especially if the required pressure is the same as that required to actuate the down-hole tool.
Various down-hole tools use pressure actuated counter mechanism and actuators, such as those described in US patents, Downhole Apparatus U.S. Pat. No. 6,223,824 and Downhole apparatus U.S. Pat. No. 6,230,808. Other counters are described in U.S. patents, Formation Isolation Valve U.S. Pat. No. 5,950,733 and Downhole tool U.S. Pat. No. 7,168,493.
In the example of the ball valve, it is sometimes desirable to close the valve when withdrawing tools from the well following an operation such as gravel packing. Closing the valve with a shifting tool, such as the Otis B shifting tool, does this. This type of tool is known in the industry.